Tracking Calcium Dynamics and Immune Surveillance at the Choroid Plexus Blood-Cerebrospinal Fluid Interface.

The choroid plexus (ChP) epithelium is a source of secreted signaling factors in cerebrospinal fluid (CSF) and a key barrier between blood and brain. Here, we develop imaging tools to interrogate these functions in adult lateral ventricle ChP in whole-mount explants and in awake mice. By imaging epithelial cells in intact ChP explants, we observed calcium activity and secretory events that increased in frequency following delivery of serotonergic agonists.

Removable cranial windows for long-term imaging in awake mice.

Cranial window implants in head-fixed rodents are becoming a preparation of choice for stable optical access to large areas of the cortex over extended periods of time. Here we provide a highly detailed and reliable surgical protocol for a cranial window implantation procedure for chronic wide-field and cellular imaging in awake, head-fixed mice, which enables subsequent window removal and replacement in the weeks and months after the initial craniotomy. This protocol has facilitated awake, chronic imaging in adolescent and adult mice over several months from a large number of cortical brain regions; targeted virus and tracer injections from data obtained using prior awake functional mapping; and functionally targeted two-photon imaging across all cortical layers in awake mice using a microprism attachment to the cranial window.

Chronic cellular imaging of entire cortical columns in awake mice using microprisms.

Two-photon imaging of cortical neurons in vivo has provided unique insights into the structure, function, and plasticity of cortical networks, but this method does not currently allow simultaneous imaging of neurons in the superficial and deepest cortical layers. Here, we describe a simple modification that enables simultaneous, long-term imaging of all cortical layers. Using a chronically implanted glass microprism in barrel cortex, we could image the same fluorescently labeled deep-layer pyramidal neurons across their entire somatodendritic axis for several months.

Synaptic plasticity defect following visual deprivation in Alzheimer's disease model transgenic mice.

Amyloid-β (Aβ)-induced changes in synaptic function in experimental models of Alzheimer's disease (AD) suggest that Aβ generation and accumulation may affect fundamental mechanisms of synaptic plasticity. To test this hypothesis, we examined the effect of APP overexpression on a well characterized, in vivo, developmental model of systems-level plasticity, ocular dominance plasticity. Following monocular visual deprivation during the critical period, mice that express mutant alleles of amyloid precursor protein (APPswe) and Presenilin1 (PS1dE9), as well as mice that express APPswe alone, lack ocular dominance plasticity in visual cortex.